Re: [PATCH RFC] [X86] Compile Option Os versus O2 on latest x86 platform

[H. Peter Anvin]

On 12/03/2009 07:03 AM, Ma, Ling wrote:
>> a key question is.. how much more memory do you have free due to -Os?
>> (because memory is cache is performance on a system level as well)
> The kernel code size from Os is 12M, that from O2 is 14M.
>> and how much less icache pressure is there?
> From perf stat report, cache reference(unified cache) from O2 is almost the same with Os.

The icache pressure was substantially higher (by ~10%) in the reports
that I saw.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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